In wireless communication applications, generally, power amplifiers are designed, e.g., sized and tuned, to accommodate worst case signals and/or transmitter configurations while meeting in-band and out-of-band distortion requirements. Designing amplifiers having increased output power to avoid higher inter-modulation (IM) distortion levels, for example, to achieve a required Adjacent Channel Leakage Ratio (ACLR), increases current drain, which results in greater heat dissipation and reduced battery life in mobile terminals.
In some wireless communication networks, certain mobile device transmitter channel configurations result in higher power amplifier (PA) inter-modulation (IM) distortion when the PA has inadequate headroom. The IM distortion may be indicated by peak-to-average ratio (PAR) information or by some other metric correlated to the distortion levels. The PA headroom is a measure of the power margin available for producing higher levels of RMS output power for a given reference signal or transmitter configuration, and/or for amplifying signals having a higher peak-to-average power ratio (PAR) at a maximum rated RMS power level.
It has been proposed to schedule around mobile device transmitter configurations corresponding to certain data rates or transport-format combinations (TFCs) that would increase inter-modulation distortion (IMD) beyond a threshold.
The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description thereof with the accompanying drawings described below.